The present invention relates to a clamp for tubes, hoses or analogous commodities. More particularly, the invention relates to a clamp which does not require the customary worm drive for applying requisite tensional stresses and which is provided with means for indicating when a predetermined tension has been reached.
Clamps of the above outlined type are already known and are used, for example, to secure a hose on a nipple in an automotive vehicle or the like. A known clamp of this type has an elongated band the end portions of which overlap each other to form a loop surrounding the hose or a similar article. Each end portion is provided with a projection and such projections can be engaged by a tool which exerts a tensioning force in a direction to cause the end portions to overlap more, i.e., to reduce the size of the loop. One of these projections is a cup-shaped bead which is pressed from the material of the end portion; the wall thickness of the bead in the vicinity of the end portion is reduced along the entire circumference of the bead so as to define a weakened zone. When the maximum permissible tensioning force is reached, the projection breaks loose along the weakened zone and further tensioning (which could cause damage to the hose and/or to the nipple) is precluded. The visually detectable absence or presence of the projection indicates whether the clamp has been properly tensioned or not.
The aforedescribed conventional clamp exhibits certain disadvantages. Thus, the edge along which the projection has been broken off is usually quite sharp and may cause injury to workmen in the manufacturing plant or to others who have to deal with the clamp at a later time. If the clamp is employed in a mass producing plant, e.g., in an automobile manufacturing plant, piles of broken away projections will lie about so that they constitute a nuisance or even a hazard to the attendants. Last but not least, there is the danger that broken-away projections may drop into sensitive pieces of machinery, e.g., into an open engine block, where they can cause serious damage.